Nick Clegg is today launching his £1bn flagship scheme to get young people into work amid accusations that the government has been complacent over youth unemployment.

The Deputy Prime Minister - who has championed the plan in the coalition - will say the start of the Youth Contract offers a route into work for young people, creating at least 410,000 new jobs over the next three years.

However Labour last night released figures showing the numbers of under 25-year-olds out of work has more than doubled since the start of last year when Clegg reportedly first raised the issue in Cabinet.

According to the figures calculated by the independent House of Commons Library, the numbers of 18 to 24-year-olds out of work for more than six months have risen from 53,000 to 107,000 - a 102% increase.

Those out of work for nine months or more increased from 29,000 to 40,000 - a jump of 144%.

Unemployment Minister Chris Grayling denounced the figures as a "complete distortion of the truth", saying long term youth unemployment had "barely changed" for two years.

Under the Youth Contract, first announced last November, firms will be offered £2,275 "wage incentives" to take on up to 160,000 under 25s, while the scheme will also create an additional 250,000 work experience placements.

The supermarket chain Morrisons, together with E-on, Phones4U, and Barclays have agreed to invest the wage incentives they receive in charities which train up young people who lack the skills needed for the world of work.

"We're determined to tackle youth unemployment and set young people on the path to work before long-term damage is done," Clegg said.

"Today is a major moment for Britain's unemployed young people. The message is clear - if you're under 25 and don't have a job, we are putting the money in to get you earning or learning through the Youth Contract. If you want to work or train, then we - together with businesses - will help you."

However Shadow work and pensions secretary Liam Byrne said his claims were belied by the rising numbers of young people out of work.

"Nick Clegg likes to brag that he warned the Cabinet about the youth jobs crisis in January last year, but his words haven't got a single young person into employment," he said.

"Instead, the number of young people out of work for over a year has more than doubled whilst his government failed to produce any alternative to Labour's successful Future Jobs Fund.

"Complacent ministers have finally come up with their Youth Contract but the truth is it won't guarantee anyone a job. It's too little, too late and a million young people out of work will rightly wonder what has been going on."